More children 5 years old and younger are being exposed to marijuana, according to a recent study LiveScience reported.

Researchers at Nationwide Children's Hospital found that the risk of young children swallowing, breathing in or otherwise being exposed to marijuana have rose 147.5 percent from 2006 through 2013 across the United States. The rate increased almost 610 percent during the same period in states that legalized marijuana for medical use before 2000.

"The high percentage of ingestions may be related to the popularity of marijuana brownies, cookies and other foods," Henry Spiller, co-author of the study and toxicologist, said in a statement. "Very young children explore their environments by putting items in their mouths, and foods such as brownies and cookies are attractive."

For the study, researchers collected and analyzed data from nearly 2,000 young children who "reported to Poison Control Centers in the United States for marijuana exposure from 2000 to 2013," LiveScience reported.

They found that most exposures resulted in only minor clinical effects, but some children experienced coma, decreased breathing, or seizures, Times of India reported. The main psychoactive ingredient of marijuana, THC, can be especially high in marijuana food products, and that may have contributed to some of the observed severe effects. More than 18 percent of children who were exposed were hospitalized. These hospital admissions were likely due not only to the clinical effects, but also the need to investigate the circumstances that lead to the exposure in the home.

"Any state considering marijuana legalization needs to include child protections in its laws from the very beginning," Gary Smith, senior author of the study, said in a statement. "Child safety must be part of the discussion when a state is considering legalization of marijuana."

The findings are detailed in the journal Clinical Pediatrics.